Ram type wood reducing apparatus



H. E. ERICKSON 2,945,521

RAM TYPE woon REDUCING APPARATUS 2 Sheets-Sheet 1 July 19, 1960 Filed March 3, 9

o N n Harold EEmckson INVENTOR.

2 Sheets-Sheet 2 H. E. ERICKSON RAM TYPE WOOD REDUCING APPARATUS July 19, 1960 Filed March 5, 1959 Qmi Harold E.Er.ickson INVENTOR.

fl-H' United States Patent "ice M I YPE'WOOD REDUCING -T-US Harold E. Erickson, Auburn, Wash, assignor of one-half to Dale L. Schubert, and one-half to Industrial-Development Co.,.Tacoma, Wash a corporation of Washington Filed Mar. 3, 1959, Ser. No. 796,805 6 Claims. (Cl. 144-162) Various types of wood reducing apparatus have been devised heretofore for flaking wood blocks or logs by feeding them' again'st a cutter. However, such tYl of apparatus have been difficult "to feed, particularly lithe feed blocks or logs have been of random dimensions; have failed to produce a comminute'd Wood product of sufficiently uniform dimensions to produce a composition board of uniform properties; or have had a relatively low production rate. It is the general object of thepre'se'nt invention to provide wood reducing apparatus whichevercomes these disadvantages.

In the drawings: I y

Fig. 1 is a rear elevation of the herein described wood reducing apparatus;

Fig. 2 is a section taken along line 2--2 of Fig. 1;. and

Fig. 3 is a schematic diagram of an hydraulic circuit which may be employed in the apparatus of Figs. 1 and 2.

Generally stated, the Wood reducing appa ratus of my invention comprises ram feed means reciprocata'bl'e between advanced and retracted positions for feeding apiece of Wood to a cutter. Hold down means are positioned for holding the wood piece as it is reduced by the cutter.

First control means are provided for reversing the direction of motion of the ram feed means as the hold down means becomes engaged with and disengaged from the piece of wood. Second control means then. are present for throttling down the speed of the ram feed means during its working cycle and for accelerating the speed thereof during its non-working cycle. 7

As a consequence, the apparatus operates at a high rate of speed throughout the entire period of time during which it is being charged with a new piece of wood regardless of the fact that such pieces may vary substantially in diameter. Hence lost time is kept at a and the production rate at a maximum.

Considering the foregoing further and with. particular reference to the drawings: y

The apparatus is housed in a frame which includes frame members 10, exterior plates 12, and a guide plate 14. The frame supports a motor 16 coupled to a cutter 18 rotatably mounted in bearings 20, -22. The cutter may be variously constructed as required to cut flakes or chips from wood logs or blocks fed to it. It operates in con- 2,945,521 Patented July 19, i960 2 junction with an anvil 24 and the flakes produced are discharged through a guide chute 26.

The logs arefed cross grain to the cutter 'by a mm assembly drivenby a hydraulic cylinder 30. This cylinder is trunnion-mounted between tabs'32 which are welded to thecentral portion of a cross 'piece'3'4 extending between side plates I2.

The piston rod of cylinder '30 is pivotally connected to tabs 36 welded to a cross barg38, the axis of which is substantially parallel tothe a'xi'sof cutter head 18. Cross bar 38 is supported by a pair of arms 40 keyed to a horizontal, 'pivotally mounted shaft42. It supports a plu- =r-a1ity of spaced, parallel, serrated plates 44, the teeth of which are arranged on an arc concentric with the periphe'r'y of cutter head -18. Their function is, to engage -a log and force it at a uniform feed rate against the cutter head for reduction intoflakes.

As the log is thus reduced it is supported oni'a grid composed of spaced, parallel plates 46 mounted on a cross bar '48 supported between arms 50. The latter are mounted on shaft 4 2 on which they turn freely.

The piston rod 'of a fluid operated cylinder 52 is pivotally connected to tabs 54 on cross bar,48.. Plates 46 thusform a floor upon which the log is supported and across which it slides as it is fed to the cutter head. However, it may be withdrawn by operation of cylinder 50 as required for cleaning or servicing.

Hold down means cooperating with ram plates 44 and grid plates 46 are provided for holding the log securely as it is reduced by the cutter head Such means comprise a plurality of vertical, parallel, hold down arms 56 the lower end of each of which mounts an offset, inwardly directed guide shoe 57. The upperend of each armis connected-by a pin 58 to a substantially horizontal supporting arm 60. Each of the latter is pivotally mounted on a-shaft 62 by means of bearings 64. The lower portion of each hold down 'arm 56 is pivotally connected by pin '66 to a substantially horizontal supporting 68 pivotally mounted by bearings 70 on a supporting shaft 72. 1

Su porting arm-s 60, 68 remain substantially arallel to each other at all times. Accordingly, pantog'raph action maintains the working ends-of hold down arms 56 closely adjacent the periphery of cutter head '18, but without coming incontact with it. y 7

Hold down arms 56 are maintained resiliently in pressure contact with the log by means of air cylinders 74, one for each arm, The piston rod of-eaeh cylinder ca rries a cross head 76 which is pivotally connected to the corresponding arm by means of pin 66.

Air under constant pressure is applied to cylinders '74, which accordingly act resiliently, continuously urging the arms downwardly into contact with the log, but being at the same time retractable against the fluid pressure as required to accommodate irregularities of log surface or logs of increased diameter.

Thus the log being operated upon by the cutter head is maintained securely in place by the serrated edges of plates 44, the grid floor formed by plates 46, and the lower surfaces of vertical hold down arms 56. .As a consequence, it can be advanced at a \uniform ieed rate against the cutter head. and flakes 'o'f uniform dim nsions are produced With filitlinlllm :fonnation Of splinters and sticks.

After each log has been reduced, cylinder 30 retracts. This withdraws the ram assembly from the cutter head so that a new log can be introduced. It is a particular feature of the present invention that means are provided for measuring each log and correspondingly controlling the speed rate of the ram assembly so that it moves rapidly when it is not working, but more slowly and at the required rate when it is working, irrespective of the diameter of the log. This factor materially increases the production rate of the apparatus.

Accomplishment of this result is achieved by including in the apparatus first control means for reversing the direction of motion of the ram feed means as the hold down means becomes engaged with and disengaged from the piece of Wood, and second control means for throttling down the speed of the ram feed means during its working cycle and for accelerating the speed thereof during its non-working cycle.

Both control means operate through a circuit illustrated schematically in Fig. 3. which operates the feed ram, is double acting and supplied with hydraulic fluid under pressure by pump 80 driven by motor 82 and drawing fluid from a reservoir 84 through conduit 86. In the advancing cycle of the ram, the fluid is introduced behind the piston of cylinder 30 via conduit 88 which includes a mechanical reversing valve 90. As indicated, this valve includes two sections the first of which, section 92, provides direct flow of fluid to the rear of cylinder 30, and the second section of which, section 94, reverses the direction of such flow.

During the advancing stroke, fluid is exhausted from ahead of the piston and cylinder via conduit 96 which divides into three parallel conduits 98, 100, -102 and which thereafter passes through reversing valve 90.

Conduit 98 includes a throttle valve 104, conduit 100, a check valve 106, and conduit 102, a mechanically onoif valve 108 including an open section 110 and a closed section 112.

Operation of reversing valve 90, and hence reversal of the feed ram assembly driven by cylinder 30, is accomplished by taking advantage of the oscillating movement of arms 40 which support the ram assembly. As indicated particularly in Fig. 2, one of such arms carries a laterally extending guide 120 in which works a slide 122 on which are mounted a pair of spaced stops 124, 126. One end of slide 122 is pivoted to one end of a bell crank 128 mounted on the inner face of frame plate 12. The other end of the bell crank is notched to receive a spring pressed detent 130. Also, it is pivoted to one end of a rod 132, the other end of which is connected to reversing valve 90 and operates the same.

Operation of on-off valve 108. and hence acceleration Hydraulic cylinder 30,

and deceleration of the speed of the feed ram assembly,

is accomplished by taking advantage of the vertically reciprocating movement of hold down arms 56 between the lowered position of Fig. 2 wherein a log is not being acted upon by the cutter, and an elevated position wherein a log is being reduced by the cutter. To this end, shaft 62 supports a freely rotatable sleeve 134 (Fig. 1) to which is rigidly afiixed a horizontally extending arm 136 provided with a cap piece which overlies one of arms 60.

Also rigidly afiixed to sleeve 134 is a horizontally extending lever arm 138. The upper end of a connecting rod 140 is pivoted to the outer end of lever arm 138, the lower end of the rod being pivoted to one end of a bell crank 142 pivotally connected to the frame of the apparatus. The other end of the bell crank is pivotally connected to a spring-pressed rod 144 which in turn operates on-oif valve 108'.

Operation Assuming that the apparatus is in the position illustrated in the drawings, with the ram feed completely advanced, and the hold down arms 56 at the lowermost point of their vertical travel, as would be the case at the conclusion of reduction of a log by cutter 18, and just prior to the introduction of a new log:

At this point in the operating cycle it is desired to reverse the ram as rapidly as possible, to introduce the new log, and then to advance the ram as rapidly as possible until it engages the new log.

In this position of the apparatus, the reversing segment of reversing valve 90 is in operative position, as is the segment of on-oif valve 108. Accordingly fluid pumped by pump passes through conduit 88, through valve 90, through the upper segment of conduit 96 including parallel conduit 98, 100, 102 the valves in which are set to pass fluid, and into the forward end of cylinder 30, retracting the ram.

When the ram is sufficiently retracted, a new log is introduced crosswise into the apparatus through the opening defined in part by guide plate 14 until it rests on grid plates 46. When the ram has reached its position of maximum retraction, indicated in dotted outline position in Fig. 2, guide 120 engages stop 124, operating bell crank 128 in a clockwise direction and hence shifting valve so that section 92 thereof becomes operative and fluid is directed behind the piston of cylinder 30 via conduit 88. No change in the setting of valve 108 occurs at this point, however.

Accordingly the ram advances toward the log at full throttle. As it advances, the serrated teeth on plates 44 engage the log and drive it forwardly beneath angled guide shoes 57 on the lower ends of hold down arms 56. The inclination of these shoes is such that they act as runners, n'ding over the surface of the log and accordingly elevating the hold down arms.

This in turn operates the linkage including lever arm 138, connecting link 140, bell crank 142, and springpressed link 144, which in turn moves on-otf valve 108 to the 01f position in which valve section 112 is operative. This closes off the flow of fluid through conduit 102.

Since the flow of fluid through conduit also is cut off by check valve 106, the flow through the system is controlled entirely by the setting of throttle valve 104. Accordingly, the forward motion of the ram is immediately decelerated to the rate necessary for uniform reduction of the log by the constantly rotating cutter 18'.

The controlled forward progress of the ram continues until the log has been completely reduced to flakes. Thereupon hold down arms 56 drop down to the position of the figures, and the linkage including lever arm 138 opens on-off valve 108. The linkage operated by guide on ram arms 40 also operates reversing valve 90 to reverse the flow of fluid and hence reverse the direction of movement of the ram. The cycle then repeats itself at intervals determined by the size of the logs introduced into it, without loss of time caused by retarded ram travel during its non-working cycle.

It is to be understood that the form of my invention herein shown and described is to be taken as a preferred example of the same and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of my invention or the scope of the subjoined claims.

Having thus described my invention, I claim:

1. Wood reducing apparatus comprising a cutter, ram feed means reciprocatable between advanced and retracted positions for feeding a piece of wood to the cutter, hold down means positioned for holding the wood piece down as it is reduced by the cutter, first control means for reversing the direction of motion of the ram feed means as the feed means reaches advanced and retracted positions and second control means for throttling down the speed of the ram feed means during its working cycle and for accelerating the speed thereof during its non-working cycle.

2. The wood reducing apparatus of claim 1 wherein the second control means is connected to and operated by the hold down means.

3. The apparatus of claim 2 wherein the hold down means comp-rises at least one arm mounted for exerting pressure downwardly on the Wood and shiftable between an elevated position assumed when the wood is being reduced by the cutter and a lowered position assumed after the wood has been reduced by the same.

4. The apparatus of claim 3 wherein the arm is lowered gravitationally and is provided with a guide shoe at its lower end, whereby advancement of -a new piece of Wood by the ram feed means against the guide shoe elevates the arm and operates the second control means.

5. The apparatus of claim 1 wherein the first control means is operated by the ram feed means.

6. The apparatus of claim 1 wherein the ram feed means includes a fluid operated motor and the first control means is positioned relative to the ram feed means for reversing the flow of fluid through the motor after a predetermined operation of the ram feed means.

References Cited in the file of this patent UNITED STATES PATENTS 2,160,920 Straun June 6, 1939 2,838,080 Springate June 10, 1958 

